1. Field of the Invention
The present invention relates to an improvement of a fastener means comprising an attracting member having a permanent magnet and an attracted member having a ferromagnetic element to be attracted by said attracting member. More particularly, it relates to a fastener means wherein surfaces of the attracting and the attracted members run parallel to each other even when the surfaces of the objects to which said members are attached are not parallel to each other.
2. Prior Art
Prior art fastener means comprises, for example as shown in FIGS. 16 through 18, an attracting member having a permanent magnet and an attracted member having a ferromagnetic element to be attracted by said permanent magnet, and is used to close the opening of bags, sacks, pocketbooks, handbags and brief cases. As the attracted member N is attracted by the attracting member M by the force of the permanent magnet 300 of the member M, the members M and N must be attached to surfaces T and T' respectively of an object in such a manner that the attracting surface m and the attracted surface n respectively thereof are in close contact with each other, as shown in FIG. 16.
In the fastener means shown in FIG. 16, the surfaces m and n respectively of the member M with the permanent magnet 300 and the member N with the ferromagnetic element 301 are brought in contact without gap in between, so that the magnetism of the permanent magnet 300 constituting the member M is guided toward the ferromagnetic element 301 of the member N under minimum reluctance for effective attraction. The close contact between the surfaces m and n of the members M and N, or that the members M and N are attached to the objects T and Tn' to parallelize the two surfaces m and n, is essential for this type of fastener means.
However, two things are rarely parallelized in practice when they are to be fastened by a fastener means. As shown in FIG. 17, the surfaces t and t' of the objects T and T' to which the members M and N are attached are often not parallel to each other. For example, the opposing surfaces at the opening of a bag, the cover of a handbag and the opposing surface of the body, or the surface of a door frame and that of the door which closes the door frame usually oppose each other at a given inclination, and the member N is often attracted to the member M in an inclined state.
When the surfaces t and t' of the objects T and T' respectively on which the members M and N are attached are not parallel to each other, their respective surfaces m and n are abutted against each other at an inclination that corresponds to the inclination occurring between the surfaces t and t'. This means that a space S is formed between the surfaces m and n when the two members M and N are attracted to each other to be in what is substantially called a point contact or a line contact.
Generally, a permanent magnet functions most efficiently when there is minimum reluctance between the permanent magnet and a substance such as ferromagnetic element which is to be attracted by the magnet. Thus, when there is a space S between the attracting member M and the attracted member N as shown in FIG. 17, it is defective in that magnetism of the permanent magnet 300 cannot be effectively utilized for attracting the member N.
When the surfaces L and t' of the objects T and T' to which the members M and N are to be attached are not parallel to each other as shown by the solid line in FIG. 18, it becomes difficult to maintain a planar contact of the member M with the member N in case an impact is applied on the objects T and T' even if they are fastened by the attraction of the member N to the member M by bringing the member N in close contact with the member M, as shown by the dot-and-chain in FIG. 18. Moreover, when applied with such impact, the members M and N are inconveniently brought to the state shown by the solid line in FIG. 18.